DP, those lights are fine, except if you plan on SPS
corals in the future, they will need to be kept near the top with the 150w MH
's. The same fixture with 250w bulbs would probably be better and shouldn't cost much more.
Welcome to the site timmy.
If you only got a 2 bulb T5 fixture for your 75, that is considered low light. You will be somewhat limited on what corals you can keep.